Abstract: An electrical data filter is provided for reducing noise reception and generation for data signal which is transmitted differentially on two conductors constituting the twisted-pair cable. The data filter includes an in-line transformer and a shunt transformer. The in-line transformer has a winding (i.e. the primary or secondary) in series with each line of the twisted pair. These windings are arranged so that they are wound in the same direction. Similarly, the shunt transformer includes a winding which shunts each wire of the twisted pair to ground through a series capacitor. These shunt windings are wound in opposite directions to each other.